[IR] Dump IdSignatures and mangled names in irText tests

The reason #1 for this feature is that we want to test IdSignatures
generated for declarations. Currently, there is no (easy) way to ensure
that a change in the signature building logic doesn't cause any breaking
changes wrt klibs.

Now, most IdSignatures include hashed mangled names in them, so even if
we catch a regression where the included hash changes, there would be no
way of knowing immediately what caused it, unless we'd also have mangled
names in the expectations.

The reason #2 is to test the manglers themselves. Currently, there are
no tests for them. They heavily duplicate each other, this is already
causing issues (see KT-57427) that would be very hard to catch without
these tests.

^KT-58238 Fixed

compiler/testData/ir/irText/errors/unresolvedReference.sig.kt.txt

@@ -0,0 +1,40 @@
+// CHECK:
+//   Mangled name: {}test1
+//   Public signature: /test1|6005685442305498193[0]
+val test1: ErrorType
+  // CHECK JVM_IR:
+  //   Mangled name computed from Ir:         #<get-test1>(){}<ERROR CLASS>
+  //   Mangled name computed from Descriptor: #<get-test1>(){}<Error class: unknown class>
+  //   Public signature: /test1.<get-test1>|-4817139884021780494[0]
+  get
+
+// CHECK:
+//   Mangled name: {}test2
+//   Public signature: /test2|2517758057000911509[0]
+val test2: ErrorType
+  // CHECK JVM_IR:
+  //   Mangled name computed from Ir:         #<get-test2>(){}<ERROR CLASS>
+  //   Mangled name computed from Descriptor: #<get-test2>(){}<Error class: unknown class>
+  //   Public signature: /test2.<get-test2>|1859255286326922853[0]
+  get
+
+// CHECK:
+//   Mangled name: {}test3
+//   Public signature: /test3|7677556066983021166[0]
+val test3: ErrorType
+  // CHECK JVM_IR:
+  //   Mangled name computed from Ir:         #<get-test3>(){}<ERROR CLASS>
+  //   Mangled name computed from Descriptor: #<get-test3>(){}<Error class: unknown class>
+  //   Public signature: /test3.<get-test3>|-2322568342617474229[0]
+  get
+
+// CHECK:
+//   Mangled name: {}test4
+//   Public signature: /test4|-9115637610245762085[0]
+val test4: ErrorType
+  // CHECK JVM_IR:
+  //   Mangled name computed from Ir:         #<get-test4>(){}<ERROR CLASS>
+  //   Mangled name computed from Descriptor: #<get-test4>(){}<Error class: unknown class>
+  //   Public signature: /test4.<get-test4>|-5181690683324812065[0]
+  get
+